The mission of the Minnesota Obesity Center is to find ways to prevent weight gain and secondarily the onset of obesity and complications of obesity. Obesity is clearly a major source of illness and death, and is the most common nutritional ailment in the United States. Despite its prevalence, there is little known about effective measures to prevent obesity, and therefore its attendant complications. Further, it is well known that obese individuals can more easily lose weight than maintain the loss. It now seems clear that the emphasis should be prevention of initial weight gain, and failing that, prevention of regain after weight loss. With the mission of prevention defined, our vision establishes three goals: 1) find the underlying problems that lead to obesity, 2) identify behaviors that lead to obesity and find ways to help change those behaviors, and 3) determine public health and public policy measures that will reduce the frequency and severity of obesity. Our Center is primarily a research center, so we plan encouragement and support of studies directed at these aims. With respect to these goals, the role of our center is to: assist principal investigators in conducting relevant research by providing resources through the core system;stimulate new interest and new collaborations in research into obesity, eating disorders and energy metabolism;support new research efforts in these areas related to obesity;and support education in obesity and eating disorders in our academic and public communities. The Minnesota Obesity Center has a strong and diverse research base consisting of 60 active investigators with 114 funded projects in obesity, energy metabolism and eating disorders. We propose the establishment of five core facilities including: 1) Administration will provide vision, leadership, and oversight of other core activities, 2) Obesity and Energy Metabolism Core will provide the latest tools for developing and evaluating gain-offunction and loss-of-function models and the techniques to assess the consequences at the level of gene and/or protein expression, 3) Disordered Eating Assessment Core will assist ONRC investigators in the assessment of disordered eating and other psychopathology, and the development of interventions for such disordered eating, 4) Epidemiology and Intervention Core is to make high quality services for epidemiological and behavioral intervention studies available to ONRC participants, 5) Metabolic Studies Core laboratory will provide access to established and state-of-the-art methods for studying energy metabolism and nutrient partitioning at the whole body level in humans and animals. In addition, resources for pilot/feasibility projects and an educational program will be established.